Door locking system for lockless lift-shaft doors



July 25, 1967 3,332,516

noon LOCKING SYSTEM FOR LOCKLESS LIFT-SHAFT moons Filed Feb. 26, 1966 A. REINKQE 2 Sheets-Sheet 1 United States Patent ice 3,332,516 DOOR LOCKING SYSTEM F011 LOCKLESS LIFT-SHAFT DOORS August Reinke, Widenhofkamp 1, Radevormwald, Germany Filed Feb. 24, 1966, Ser. No. 529,867 Claims priority, application Germany, Feb. 26, 1965,

Sch 37,672; July 8, 1965, Sch 37,346

4 Claims. (Cl. 187-61) The invention relates to door locking devices for lockless lift-shaft doors, in which the lift-shaft door is locked by means of a locking bolt shiftable in an axial direction and permanently connected with a bolt switch, whereby the locking of the door and the switching-on of the control circuit for the hoisting gear train can be etfected by a slide arranged on the lift cage only when the door of the lift-shaft is closed.

For reasons of safety, in accordance with the technical regulations in force for passenger and goods lifts all liftshaft doors of a lift must be closed and locked, with the exception of the door of the cage. This regulation is met by door fastenings which contain a lock-boltusually in the form of a cylindrical bolt, which in order to lock the closed door penetrates into a corresponding aperture therein. The locking bolt must be held in the locked position by spring tension, gravity or magnetic force and must not operate ineffectively or unreliably even with rough use, if the door-leaf drops or due to atmospheric influences.

Furthermore it must only be possible to switch on the driving system when all the doors of the lift-shaft are closed and locked. This regulation is met by means of a contact-piece (permanently connected with the lock-bolt) of a bolt-switch, which closes the control circuit of the driving system only when the lock-bolt has engaged in the door. 1

However, the switching-on of the control circuit must also be prevented when in the event of a breakdown the lock-bolt is released when the door of the lift-shaft is not closed. In order to satisfy this regulation the door-locking system must have a special fail-safe locking device, which in the event of an unclosed lift-shaft door either positively prevent-s the lock-bolt from engaging or renders the switching on of the control circuit by the lock-bolt impossible.

All the door-locking devices have in common their actuation by a slide arranged on the lift cage, which unlocks the door of the lift-shaft via a roller lever when the lift arrives at a stop.

Variou methods have been suggested and adopted in order to satisfy these regulations.

In one known embodiment the closing of the control circuit when the lift-shaft door is not closed is prevented by designing the bolt switch as a wiper contact. When the door locking device engages, the lock bolt goes into the closed lift-shaft door to a depth determined by a stop. In this po ition the control circuit for the driving unit is closed by the bolt-switch connected with the lock-bolt. If the door of the lift-shaft is not closed, the lock-bolt,

in engaging the door locking system, thrusts beyond its closing position into vacancy, and the contact of the boltswitch is again broken.

This type ha the disadvantage that the lock-bolt, even when the lift-shaft door is not closed, may be impeded in its free movement by jamming, due to dirt or other external influences, and therefore the control circuit is not broken. Moreover, it must be regarded as a drawback of this arrangement that any interruption of the control circuit may again be cancelled by lifting the lock-bolt by hand and thus the fail-safe device can be disabled in a simple way.

7 3,332,516 Patented July 25, 1967 In another embodiment the engagement of the lockbolt in the door is supervised by a second locking means incorporated in the lock-bolt itself. This second locking means becomes effective if the door-locking device is tripped when the lift-shaft door is open, by the fact that the upstroke of the door-bolt is restricted to a short run, thereby preventing the closing of the control circuit by the bolt-switch connected with the lock-bolt.

This type of fail-safe lock has the disadvantage that the locking elements inside the lock-bolt, owing to their small dimensions, are exposed to high mechanical stresses and it is no longer possible to check their reliability of operation in the mounted condition. This type has the further drawback that the fail-safe locking device can be disabled by simple means, such as screwdrivers or nails introduced into the hole for the lock-bolt.

Devices are also known, in which the action of a magnetic field of force is utilised for the fail-safe locking devices on door-locking systems. A powerful permanent magnet mounted in the door acts, when the lift-shaft door is closed, via a hinge-armature in the door-locking device mounted in the door-frame on an articulated-lever rodding system. When the lift-shaft door i open and the lock-bolt drawn back, this system is in the beyond-deadcentre position and blocks the thrusting movement of the lock-bolt. The magnet in the door will pull the armature into the lock housing only when the lift-shaft door is closed, and said magnet will then bring the articulated lever into a position which, by bending-in it leaves when the lift-shaft door is locked and connects the lockingof the lock-bolt.

Since the articulated lever system is held in the blocking position'only by its own weight, the locking of the door is dependent upon position. Mounting is possible only with horizontally-acting lock-bolts in the closing edge of the door-frame, and it can be used only with single-leaf doors. This arrangement, however, has the disadvantage, as compared with the locking device acting vertically in the top edge of the door-frame, that if the door drops in the course of time it is no longer possible to ensure that the lock-bolt will go into the door Without fail. Furthermore the low specific Weight of the articulated lever-s renders the reliable operation of the locking mechanism very dependent upon the easy mobility of the hinges which may be badly affected by dust, resinification of lubricants and so on. The function-conditioned use of a high-power magnet with suitably expanded field of lines of force means that also adjacent iron parts affect the method of operation. It is therefore necessary to compensate such influence, which varies from one case to another and differs in operation, by means of an adjustable spring.

In another embodiment it is attempted to meet the requirements mentioned herein by the fact that the thrusting movement of the lock-bolt is effected directly by permanent magnets. The lock-bolt in this case is arranged at one end of a two-armed lever and a magnet is arranged at each of its two ends. Two magnets which, when the door is closed, are opposite to the magnets in the doorlocking device, are let into the lift-shaft door. The magnets in the door are polarised in such a way that by attracting and repelling the magnets fixed on the lever they exert rectified torsional moments and bring the lockbolts into engagement.

With this arrangement the counteraction of magnetic force and spring tension and/or gravitational force is unfavorable, since the opposing forces act in the unblocking direction and must be carefully tuned to the magnetic force. Vibrations and impacts to which the door is inevitably exposed, particularly in the case of goods lifts, by transport processes, may also have an undesirable efiect, all the more so, since all the stresses of the lockbolt, contrary to the otherwise usual types, are not taken by a guide bushing, but strain the needle bearing of the lever pinion.

It is the object of the present invention to provide a door-locking device for lockless lift-shaft doors, in which the switching on of the driving mechanism when the door is not closed is prevented by a particularly simple magnetic fail-safe locking device.

In accordance with the invention it is proposed to connect the movable permanent magnet, co-operating with the door magnet, rigidly with a structural unit which is adapted to be displaced in the axial direction and to maintain said structural unit, by its own weight and/or by spring tension, in a position in which it blocks the movement of the lock-bolt when the lift-shaft door is not closed. The structural unit in that case is in particular designed as a bolt which has a stop-pin co-operating with a stop-catch which is connected via a lever with the lockbolt carrying the lock-switch.

When the lift-shaft door is closed, the two permanent magnets stop with the similar poles facing each other at a short distance. By reason of the repellent power action, exerted by the magnet arranged in the door upon the moving magnets of the fail-safe locking device, the movable magnet and the bolt permanently connected therewith is raised and releases the stop-catch of the operating lever for the door-locking bolt, so that the latter can be moved freely. If in the regular course of the switching-on sequence, the electromagnetically actuated slide on the lift cage is switched on, the latter also releases the doorlocking bolt via a roller lever resting on the slide and a pull-rod, so that the door-locking bolt can penetrate into the door by spring tension and the lock-switch permanently connected therewith can finally switch on the hoisting mechanism.

The fail-safe locking device becomes effective if in the event of a breakdown the magnetic slide is attracted before the lift-shaft door is closed. The permanent magnet mounted in the door is then unable to lift the movable magnets of the fail-safe locking device and the control lever of the lock-bolt is locked, so that also the lockswitch connected with the look-bolt cannot switch on the hoisting mechanism.

Since the locking position of the door can only be magnetically controlled, and therefore no control forces for mechanically moved parts must be used, and furthermore the path and consequently the air-gap of the magnet are very small, the magnet may be a very small one, with the result that the magnetic field is very concentrated, and magnetisable components in the vicinity of the magnet, which might attenuate the field of force, have no effect.

The invention will be explained in the following with reference to an embodiment and in the drawings:

FIGURE 1 shows the state of the door-locking system when the lift-shaft door is open and unlocked.

FIGURE 2 shows the state of the door-locking system when the lift-shaft door is closed and locked.

FIGURE 3 shows the state of the door-locking system if the lift-shaft door is open and the fail-safe locking device has come into action.

FIG. 4 is a fragmentary diagrammatic front view, partly broken away, of an elevator system; and

FIG. 5 is a section through the elevator system.

The performance of the elevator controls, door lock and locking device is illustrated in FIGS. 4 and 5. The lift cage 22 is in this instance on the second floor. The locking device 23 on the lift cage is released and the slide 6 is by spring action forced against the roller lever 5, whereby the lock bolt 2 is withdrawn from the bore in the door 24 and the latter may be opened. At the same time, the switch 25, which is firmly connected with the bolt 2, is opened.

On the first and third floors, at both of which the lift cage is absent in this instance, the doors are closed and locked. On activating the locking device, the roller level of the door lock is released and the lock bolt is advanced by the action of the spring 26. In closed condition of the lift-shaft door the action magnet 12 deactivates the failsafe locking system so that the bolt may advance into lock position in which the lock switch is closed, i.e., the lift cage leaves the second floor.

The slide of the locking device is sufficiently retracted so that the roller lever is not actuated on passing the several floors.

In open condition of the door, the catch piece and its bolt are forced into catc-h position. If the locking device is then activated, the lock bolt advances only to an intermediate position in which the bolt switch cannot be closed. Accordingly, the lift cage cannot leave the floor.

The door-locking system is mounted in a housing 1 of non-magnetisable material, preferably light metal.

When the lift-shaft door is open the lock-bolt 2 is drawn back against the force of the helical spring 7 via the bellcrank 3, pull-rod 4 and the roller lever 5 arranged in the lift-shaft next to the door, through the slide 6 connected with the lift cage and which has been released. The member 11 carrying the locking projection 8 is displaceably supported in the housing 1 in its axial direction. On its end facing the lift-shaft door it carries a permanent magnet 12 and when the door is opened comes into the position shown in FIGURE 1 as a result of its own weight and the force of the helical spring 13 acting in the same direction. In this position the stop catch 9 permanently connected to the bellcrank 3 and the projection connected with the member are opposite each other and so prevent the inadvertent lowering of the lock-bolt 2 and switching-on of the control circuit for the hoisting mechanism by the interlock switch 10. At its upper end the member 11 has an oblique end surface 14, with which a pin 15 co-operates, which is rigidly fixed to the pull rod 4, and thus when the door is unlocked this exerts a force in the same direction of movement as the gravitational force and the force of the helical spring 13. This positive displacement then also causes the locking of the lock-bolt 2 when the lift-shaft door is open, if due to damage or breaking of spring 13 and at the same time its jamming, the free movement of the member 11 is to be prevented.

When the lift-shaft door 20 is closed, then, according to FIGURE 2, the magnet 21 mounted in the door is close underneath the magnet 12. The corresponding polarity of the front surfaces of the magnets which face each other produces a powerful repellent force, which pushes up the movable magnet 12 and the blocking projection 8 connected therewith by the member 11 against their own weight and the spring tension. The locking projection 8 and stop catch 9 are thereupon out of engagement. When the slide 6 is retracted the lock-bolt 2 and the control members connected therewith, i.e. the bellcrank 3, push rod 4, roller lever 5have assumed the condition shown under the action of spring 7. The lock-bolt has penetrated the closed door 20 and the switch 10 connected with the lock-bolt 2 has switched on the control circuit of the hoisting mechanism.

If, in the event of -a breakdown, the pull magnet of the slide 6 is switched on before the door of the liftshaft has closed, the fail-safe locking system comes into action and prevents the switching-on of the driving mechanism. The door locking system then adopts the state shown in FIGURE 3. Since in the assumed breakdown the door of the lift-shaft is not closed, the magnet 21 mounted in the door is unable to act upon the magnet 12 of the fail-safe locking system, which remains in the position induced by gravity and spring tension. The spring 7 of the lock-bolt attempts to move lock-bolt 2 downwards, since the retracted slide 6 has released roller lever 5; but this movement is prevented because the stop-catch 9 of the bellcrank 3 is resting against the projection 8. The blocking of the bellcrank 3 prevents the lock-bolt 2 from extending, when the lift-shaft door is not closed, and the bolt-switch thereby switching on the hoisting mechanism despite the fact that the lift-shaft door is open. A taper 16 on the front of lockbolt 2 makes it possible for the lift-shaft door to be closed again later, even when the lock-bolt is blocked, and the locking condition shown on FIGURE 1 is to be established.

In the blocked position shown in FIGURE 3, the lowest point of the lock-bolt 2 is somewhat lower than the upper edge of the door. Consequently when the liftshaft door is subsequently closed the lock-bolt 2 is momentarily slightly raised and relieves the projection 8 which is under the pressure of the stop-catch 9, so that the magnet 12 which has come under the repellent influence of the magnet 21 through the now-closed door, can raise the stop-bolt 8 and eliminate the blocking of lever 3 and thus of lock-bolt 2.

I claim:

1. In combination with a lift cage and a lift shaft door, a locking mechanism for said door comprising a bolt mounted for axial movement to engage said door, a control switch operated by said bolt, a spring urging said bolt into its door-engaging position, a linkage controlling said bolt, a retractable slide on said lift cage for operating said linkage to retract said bolt against the force of said spring, a device for blocking movement of said linkage, said device comprising a movable member, means urging said member into its blocking position, a first permanent magnet mounted on said movable member, and a second permanent magnet mounted on said shaft door, said magnets being mounted with like magnetic poles adjacent one another and being mounted at a lateral spacing such that when said shaft door is closed said second magnet exerts a repulsive force on said first magnet whereby said movable member is displaced and said blocking device is rendered inoperative.

2. A locking mechanism according to claim 1, in which said movable member is formed with a projection and said linkage includes a catch cooperating with said projection in said blocking position of said movable member.

3. A locking mechanism according to claim 2, in which said movable member has a cam surface and said linkage has a part cooperating with said cam surface whereby, when said linkage is in a position corresponding to retraction of said bolt, said movable member is positively engaged and movement of said linkage is blocked.

4. A locking mechanism according to claim 1, in which said bolt has a tapered end portion, whereby said lift shaft door may be closed even when said bolt is in said door-engaging position.

References Cited UNITED STATES PATENTS 1,847,039 2/ 1932 Dunn 18761 1,944,471 1/ 1934 Seeger 187-61 FOREIGN PATENTS 1,014,721 12/ 1953 Germany.

EVON C. BLUNK, Primary Examiner.

H. C. HORNSBY, Assistant Examiner. 

1. IN COMBINATION WITH A LIFT CAGE AND A LIFT SHAFT DOOR, A LOCKING MECHANISM FOR SAID DOOR COMPRISING A BOLT MOUNTED FOR AXIAL MOVEMENT TO ENGAGE SAID DOOR, A CONTROL SWITCH OPERATED BY SAID BOLT, A SPRING URGING SAID BOLT INTO ITS DOOR-ENGAGING POSITION, A LINKAGE CONTROLLING SAID BOLT, A RETRACTABLE SLIDE ON SAID LIFT CAGE FOR OPERATING SAID LINKAGE TO RETRACT SAID BOLT AGAINST THE FORCE OF SAID SPRING, A DEVICE FOR BLOCKING MOVEMENT OF SAID LINKAGE, SAID DEVICE COMPRISING A MOVABLE MEMBER, MEANS URGING SAID MEMBER INTO ITS BLOCKING POSITION, A FIRST PERMANENT MAGNET MOUNTED ON SAID MOVABLE MEMBER, AND A SECOND PERMANENT MAGNET MOUNTED ON SAID SHAFT DOOR, SAID MAGNETS BEING MOUNTED WITH LIKE MAGNETIC POLES ADJACENT ONE ANOTHER AND BEING MOUNTED AT A LATERAL SPACING SUCH THAT WHEN SAID SHAFT DOOR IS CLOSED SAID SECOND MAGNET EXERTS A REPULSIVE FORCE ON SAID FIRST MAGNET WHEREBY SAID MOVABLE MEMBER IS DISPLACED AND SAID BLOCKING DEVICE IS RENDERED INOPERATIVE. 